You know the saying “You’re as young as you feel.” Well, there may be some truth to that, according to researchers at Harvard and the Massachusetts Institute of Technology.

Ellen Langer, a Harvard psychologist who studies how the mind influences the body, and colleagues reviewed the scientific literature for evidence that a person’s perception of their age might influence their health. They published their results in the journal Perspectives on Psychological Science.

In one study that Langer led, 47 women had their hair done. The women who thought their new hairdos made them look younger did look younger to objective observers, who were shown before-and-after pictures. The women who thought they looked younger also showed a drop in blood pressure.

Another study involving 4,421 men found that those who became bald at a relatively young age were more likely to get prostate cancer and heart disease than men who did not. Similarly, another study involving 2,017 men found that those who lost their hair early were more likely to develop heart disease. “We believe that the feelings associated with being older than one’s chronological age account for some of these health outcomes,” the researchers wrote.

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The researchers also described studies that found that women who had children later in life were more likely to be healthier and live longer than those who had children early, which they attributed to the fact that these mothers tend to spend more time with younger women. Similarly, people who marry younger partners tend to live longer than those who marry older partners, according to other studies.

Taken together, the research “supports the general mind/body hypothesis that when a younger mind is primed, a younger body can accompany it.” While the mechanism remains unclear, the researchers speculated that cues associated with aging can “make one unconsciously or consciously aware of old age and set in motion a series of physiological processes that can have real effects on short-term and long-term health.”